Abstract

Background

A large body of literature suggests that certain polysaccharides affect immune system
function. Much of this literature, however, consists of in vitro studies or studies in which polysaccharides were injected. Their immunologic effects
following oral administration is less clear. The purpose of this systematic review
was to consolidate and evaluate the available data regarding the specific immunologic
effects of dietary polysaccharides.

Methods

Studies were identified by conducting PubMed and Google Scholar electronic searches
and through reviews of polysaccharide article bibliographies. Only articles published
in English were included in this review. Two researchers reviewed data on study design,
control, sample size, results, and nature of outcome measures. Subsequent searches
were conducted to gather information about polysaccharide safety, structure and composition,
and disposition.

Conclusions

Taken as a whole, the oral polysaccharide literature is highly heterogenous and is
not sufficient to support broad product structure/function generalizations. Numerous
dietary polysaccharides, particularly glucans, appear to elicit diverse immunomodulatory
effects in numerous animal tissues, including the blood, GI tract and spleen. Glucan
extracts from the Trametes versicolor mushroom improved survival and immune function in human RCTs of cancer patients; glucans,
arabinogalactans and fucoidans elicited immunomodulatory effects in controlled studies
of healthy adults and patients with canker sores and seasonal allergies. This review
provides a foundation that can serve to guide future research on immune modulation
by well-characterized polysaccharide compounds.